In this competing continuation application, we plan to remain focused on the development of magnetic resonance imaging devices and methods for treatment of vascular diseases. Conventional interventional procedures, such as balloon angioplasty or intravascular stent placement, are primarily guided by x-ray fluoroscopy with contrast injections outlining the vascular lumen, but this method provides no information about the vessel wall or its pathology. Intravascular MRI (IVMRI) offers several significant advantages over other imaging techniques, in that it can provide ultra-high resolution with high contrast definition of normal and diseased vessels, which is important for the characterization of atherosclerosis. We have developed miniature, long, flexible catheter coils and loopless catheter antennae for high resolution IVMRI of the blood vessels. Using these probes, we successfully acquired in vivo ultra-high resolution images of the arterial wall. Our in vitro studies demonstrated that, using this method, it is possible to identify the three morphological layers of human arteries and characterize atherosclerotic plaques. In this study, we will test the hypothesis that MR-guided coronary artery balloon angioplasty can be carried out with high accuracy and at high speed. To be able to test this hypothesis, we plan to develop the best-performing intravascular MR probes and modify the hardware and software of existing MR scanners to enable control of the imaging parameters in the scanner room directly by interventionalists during a vascular intervention. Moreover, we will develop a real-time projection MR angiography technique that enables imaging of the blood vessels by contrast injection directly into the arteries. We will test the accuracy and the speed of the overall system on a dog model with an artificial stenosis. We believe that using these novel methods and devices will open up a new avenue for accurate, precise and radiation-free coronary interventions.